1. The Field of the Invention
The present invention relates generally to a wrench with a bearing-type clutch and/or a ratchet type mechanism. In particular, the present invention relates to a wrench with both instant engagement bearings and higher torque pawl and ratchet gears.
2. The Background Art
Various types of fasteners are used to attach two or more members together. A bolt and nut combination is one type of well known fastener. The bolt includes a male threaded end configured to engage a female threaded nut.
The driving end of the bolt, or the head, and the nut are provided with bodies of standard size and shape. The most common shape is a hexagon, or six-sided body. Other shapes are available, including a square. The head may also be provided with a hole or bore of standard size and shape. Such shapes include various stars with straight and curved sides and various polygons. In addition, such heads and nuts are provided in English and metric size ranges, such as xe2x85x9 in., {fraction (3/16)} in., xc2xc in., {fraction (5/16)} in., xe2x85x9c in., etc., or 3 mm, 4 mm, 5 mm, 6 mm, etc.
Special tools are configured to engage and drive either the head of the bolt and/or the nut. For example, a wrench typically has an open-ended jaw and a closed-ended jaw. The ends are sized and configured to mate with the bolt head or nut. Thus, wrenches typically have apertures formed in the ends with various polygonal shapes, or stars with various numbers of points. In addition, the wrenches are usually provided in sets having numerous wrenches each having jaws configured to mate with a particularly sized bolt head or nut. By engaging the bolt head or nut with the appropriate wrench, the bolt or nut may be rotated clockwise or counterclockwise in order to tighten or loosen the fastener, respectively.
One problem with the above described wrenches is that they often must be continually disengaged and re-engaged with the nut or bolt. Often, a fastener is placed adjacent another member or located in a limited space. Because the wrench has an elongated body, it may be turned only a fraction of the necessary rotation before any further rotation is impeded. Thus, the wrench must be disengaged from the head, rotated back to the starting point, re-engaged with the head, rotated until again impeded, and the process repeated until the fastener is either loosened or tightened. In addition, if the head is located where only a small rotation is possible, the wrench must also be turned over after disengaging because the handle extends at an angle from the end of the wrench. Furthermore, if the space is extremely tight, the wrench may be rendered useless because there is insufficient space in which the wrench may turn the head.
A ratchet wrench is very popular and solves many of the above identified problems with the standard wrench. The ratchet wrench has a ratchet mechanism which allows a handle of the wrench to rotate freely in one direction, but engage a driver coupled to a head of the ratchet wrench in the opposite direction. This allows the ratchet wrench to engage a head, and rotate back and forth, tightening or loosening the fastener without having to disengage the wrench from the head. The typical ratchet wrench has an elongated body with a head adapted to receive sockets of various sizes and shapes. Thus, sockets usually are provided in sets with one or more ratchet wrenches. The ratchet wrench typically has a set of teeth and a pawl which reversibly engage in one direction.
One problem with the ratchet wrench is the finite increments the wrench may be rotated backwards, known as arc swing. Conventional ratchet wrenches have a finite number of engagement points and are therefore limited in the degree they may be rotated backwards, or arc swing, by the number of the teeth. For example, if there are 60 teeth, the ratchet wrench is limited to 6 degree increments when rotating backwards before another tooth can be engaged. If the head of the bolt is located in a tight space, it may not be possible to rotate the ratchet wrench a full 6 degrees. Thus, the wrench will not be able to rotate back more than the 6 degrees to engage the next tooth, rendering the wrench useless.
Analog or bearing-type wrenches have been developed and may provide smaller arc swing, and thus may be utilized in very tight spaces. These analog or bearing-type wrenches, however, may roll under high torque conditions.
It has been recognized that it would be advantageous to develop a wrench with an infinite number of engagement points, or a wrench that instantly engages despite the amount of backwards rotation. In addition, it has been recognized that it would be advantageous to develop a wrench with a small arc swing, and capable of withstanding high torque conditions. It also has been recognized that it would be advantageous to develop such a wrench capable of operation in both directions, or a reversible wrench. It also has been recognized that it would be advantageous to develop a reversible clutch capable of instantaneous engagement and with infinite increments in the reverse direction.
The invention provides a wrench device having a bearing clutch with a small arc swing, and a ratchet mechanism capable of withstanding high torque. The wrench includes a secondary body or engagement cam rotatably coupled to a primary body having a handle and head. The primary body has a cavity forming a primary wall. The secondary body can be rotatably disposed in the cavity, and has a secondary wall generally opposing the primary wall.
A tapering space is formed between the primary and secondary walls. A bearing is movably disposed in the tapering space and movably between a free location and an binding location. In the free location the bearing allows the secondary body to rotate with respect to the primary body. In the binding location the bearing binds between the primary and secondary walls to cause the primary and secondary bodies to rotate together.
A plurality of teeth also are formed on one of the primary or secondary bodies, such as in the cavity of the primary body. A pawl is pivotally disposed on the other of the primary or secondary bodies, such as the secondary body, to engage the plurality of teeth. The pawl can pivot between a slip position and an engagement position. In the slip position the teeth slide past the pawl to allow the secondary body to rotate with respect to the primary body. In the engagement position the pawl engages in the teeth to cause the primary and secondary bodies to rotate together.
Preferably, the bearing clutch has a small arc swing relative to an arc swing of the ratchet mechanism. In addition, the bearing binds between the primary and secondary walls in the binding location when a torque is applied between the primary and secondary bodies, but may roll when an increased torque is applied. The pawl advantageously engages the teeth in the engagement position when the increased torque is applied to prevent further rotation.
In accordance with one aspect of the present invention, the cavity of the primary body further includes a smooth wall section, and a toothed section with the plurality of teeth. Both sections preferably circumscribe the cavity. Similarly, the secondary body can include a smooth wall section opposing the smooth wall section of the primary body and circumscribing the secondary body.
In accordance with another aspect of the present invention, the wrench can include displacement means for displacing the bearing from the binding location to the free location. For example, a switch or pivot member can be pivotally coupled to the primary body, and a swivel link can be pivotally coupled to the secondary body and engaged by the switch or pivot member to displace the bearings.
In accordance with another aspect of the present invention, the at least one pawl can include at least two pawls which are disposed to abut the teeth such that the pawls alternately abut the teeth. A first pawl can abut the teeth at a first rotational orientation between the bodies. A second pawl can abut the teeth in a second rotational orientation between the bodies. Thus, each single pawl abuts the teeth at rotational intervals equaling 360 degrees divided by the number of teeth, but the pawls together abut the teeth at rotational intervals equaling at least half of a single pawl, reducing the arc swing and decreasing any roll of the bearing at increased torque.
Additional features and advantages of the invention will be set forth in the detailed description which follows, taken in conjunction with the accompanying drawing, which together illustrate by way of example, the features of the invention.